Overload definite-time-limit relay.



L. C. NICHOLSON. UVCRLOAD DEFINITIE TIME LIMIT RELAY. APPLICATION HLED SEPT. 7.. 915.

1,277,249. 7 Patented Aug. 27, was

3 SHEETS-SHEET 1' I -5, VL- 9 077169 L. C. NICHOLSON. v

OVERLOAD DEFINHEIIME LIMIT RELAY.-

APPLiCAHON FILED SEPI. I. 1915.

1,277,249. lzttvntvd Aug. 27, 1918.

3 SHEEIS SHEEI 2.

\ L. c. NICHOLSON.

OVERLOAO DEFINITE TIME LIMIT RELAY.

APPLICATION mu) SEPT. 7. l9l5.

Pa fONtOd Aug. 52?, M3

3 SHEETS--SHEET 3.

' mined length of time and able cont'actor promptly to its zero position UNITED STATES PATENT OFFICE.

LLOYD C. NICHOLSON, OF BUFFALO, NEW YORK.

OVERLOAID nnrmrrn-rimn-Lmxr RELAY.

Applicationfiled September 7, 1915.

To all whom it may concern Be it known that I, LLOYD citizen of the United States, residing at Buifalo, in the county of Erie and State of New York, haveinvented certain new and useful Improvements in Overload Definite- Time-Limit Relays, ofwhich the following is a specification.

My invention relates to a relay, and more particularly to an overload definite time limit relay.

One of the objects of my invention is the production of a relay of this type that will produce a certain definite motion in a certain definite number of alternations during which an overload current of greater value than a predetermined quantity remains in the circuit.

Another object of my invention is the production of a relay that may be used to record the number of alternations of current passing through it, and whereby a time recor can be obtained of any flow of the alternating current by means of a stationary scale and a pointeror indicator co-acting therewith. r

A t'urther'object is to provide a device of this character which will respond to a cer tain predetermined flow of alternating current through its windings and thereupon cause a movable contactor to approach and touch a stationary .contactor in a predeterto return the movafter such flow of current decreases to less than the predetermined value.

Further objects are to provide a mechanism of this kind in which there are no contacts necessary to cause vibration of the armature; and to otherwise improveon evices of this type.

To these ends the novel arrangement of parts, and in the combination of elements and peculiar construction of parts to be hereinafter described and particularly pointed out in joined claims.

In the drawings,-

Figure l is' a side elevation of my improved relay showing one application of the same, the various devices being shown diagrammatically.

Fig. 2 is a side "elevation of my improved relay, a portion of the sanit being broken Specification of Letters Yatent.

C. Nrcnonson,

invention consists in the novel arrangement of devices, inthe eluded therefore the sub- Patented Aug. 27, 1918.

Serial No. 49,285. away to better illustrate parts otherwise hidden.

Fig. 3 is a plan view. Y

Fig. 4 is an end elevation viewed from the left in Fig. 2.

Fig.' 5 is a transverse section taken on line a.a, Fig. 2, the ratchet wheel and brake drum being shown in elevation.

Fig. 6 is a transverse section taken on line b b, Fig. 2, the binding post through which said line passes being shown in elevation.

Fig. 7 is a detached perspectiveview of one of the contactors of the device.

Fig. 8 is a fragmentary vertical section of the same.

' Fig. 9 is a longitudinal section through the outer end of the armature and parts connected thereto.

Referring now to the drawings in detail, like numeralsof reference refer to like parts in the several figures.

Reference being had to Fig. 1, 1O designates an alternating current generator having circuit wires 11, 12, connected thereto, said wires forming an electricv circuit in which are included solenoid operated switches 13 by means of which said electric circuit is established and broken, the 'solc-' noid-operated switches being well known to the art and therefore it is not believed necessary to show or describe them in detail.

1i designates a relay which is connected with the circuit wire 11 by means of a series transformer 15. The relay has a stationary contactor 16 and a movable contactor 17, the contactor 17 being connected by a circuit wire 18 with one of the solen'oids -19 controlling one of the switches 13, said solenoid being connected by a circuit.- wire 20 with the other solenoid 21. The movable contactor I6 is connected with one pole of a battery 22 by a wire 23, the other pole of the battery being connected by a wire 2% with the last-mentioned solenoid.

he circuit in which the solenoids are in has a battery as a source of electrical energy and may be termed a control circuit, and when the movable contactor 17 is brought into engagement with the stationary contactor 16 thesolenoids 19, 21, are energized by the battery current a predetermined length of time after the electric circuit beginsto deliver excess current, as for example when the electric circuit is short circuited. It is of courseunderstood that the coil of the relay is energized by the secondary of the series transformer, as is well known in the art. Reference being had to the relay, 25 designates a plate or base from which rise two pairs of standards or supports 26, 27, the pair of standards 26 being spaced from the pair of standards 27 and both pairs hating a laminated soft iron core or magnet 28 28 is wound with an exciting coil 29 connected to. binding posts 30, 31, which are in turn connected to the source of alternat ing current, through the transformer 15.

Interposed between the two pairs of standards or supports 26, 27, directly above the poles of the horseshoe magnet. is a pivoted armature 32 which is in close proximity to one pole 33, as at 34, but normally separated from the other pole 35, as at 36. The normal position of said armature is its ,uppermost position and it is held against an adjustable stop 37 secured to the top crossbar 38.0011- necting'the upper ends of the standards, 27.

v This adjustable stop is'shown in the form of a screw passed down through the connect: ing bar 38 and bearing with its lower end against the upper face of the armature, as at 39, said-screw being adjusted through said cross bar and being held in "any adjusted position by ajam nut 40 threaded thereon and bearing against said cross bar. The

armature is retained 'in its uppermost or.

,normal position-by an adjustable-tension device 41 which comprises a coil spring 4C2 secured at one end to a screw 43 passed through the cross bar 38 andheld in adjustopposite end of said spring being fastened to a stud 46 secured in the armature. i

The armature 32 extends beyond the pole 5 of the magnet, and at its outer end carries a ratchet actuating device 47. This. device comprises a dog 48 pivoted to the outer end of the armature, as at 49, and having an overhanging stop arm 50 adapted to bear against the upper face of said armature t'o prevent upward movement of said dog beyond a certain point. This dog is normall held in its upperniost position by a coi spring 51 having one end secured to said dog and its other end secured to an L-shaped arm 52 extending upwardly and outwardly from the armature. The magnet 28, exciting coil 29, armature 32, andparts connected thereto and carried thereby ing mechanism or -motor nism to "be now described;

A pairof standards 53 is secured -to the plate 'or base 25 and journaled in these standards is; shaft 54, said shaft'having I term actuatwhich is adapted to actuate timing and controlling mecha- "formed thereon a sto secured thereto midway between the two standards 53 a ratchet wheel 55, and at each side of the ratchet wheel betweenthe same and each standardor support 53 is a brake dial 59 secured thereto and the projecting endof said shaft having an indicating finger .60 secured thereto. The dial is therefore held against movement while the indicating finger travels in a circular path over the graduated face of said dial. The ratchet wheel 55 is arranged in line with the dog 48 and is adapted to have its. teeth engaged by .saiddog when the actuating mechanism or motor is'placed in motion or, in other words,

net.

. The plate or base is provided with a fourth set of standards 61, through which a shaft 62 is passed,"said shaft having a collar 63 secured thereto and bearing against the inner face of one of said standards. A'tension spring 64;is placed around said shaft 65, and its other end fastenedfto the opposite staridard, as at 66. One of the standards '61 is provided with akboss 67 onitsouter side to whi'ch'a collar 68 is fastened,-and extending froni'this collar is-a-stop arm 69. One end of said shaft 62 hasa gear wheel 70 secured thereto which is inflmes hwith the pinion 57.' Said gear wheel has the con,- tactor '17 extending from the rim thereof,

, which by reason ofits moving with said gear r-wheel I have termedthe movable contactor. ed position bya nut 4e and jamnut {L5, the

71 which isth'readed into the plate or. base 25,0r otherwise fastened thereto, and a top member 72 pivotally, secured to the base member, as at 7 3, said members having beveled-contacting faces 74,75, at a point beneath the'pivot 73 so that member 72 may be swung on member 71 in one direction only, and in order to retain said top member in line with said base member a flat spring when the armature is attracted by the magand has oneend'secured to said collar, as'at 76 is secured to said base member and ex- 'tends upwardly therefrom with its .upper end in contact with said top member.

Shaft 62 has rigidly secured thereto or device 77 which is adapted to normally 111' against the stop arm 69, said stop device maybe formed by reducing the diameter of the shaft 62 and bending the same at a right angle, as at 78, and thence rebending the same'at a right angle to said first right-angled portion; as at 7 9, to form a stop portion parallel with the shaft 62 and adapted to engage the underside of the stop arm viceis retained These brakes, or brake bands as they may be termed, are applied "to the brake wheels or drums during the attracted or downward movement of the armature and therefore also prevent over-shooting of the ratchet heel 55; that is to say, they prevent the ratchet wheel moving ,more than the distance it is intended the armature 32 shall causeitt'o move, which is one tooth for each downward stroke of the armature.

sition, the flexible brakes 80'are out of contact with the brake wheels or drums.

The relay serves as a motor of the vibrating armature type. The passage of alternating current through the exciting coil 29 attracts the armature 3'2, drawing it down ward until it rests against the pole piece 35 of the core or magnet 28. From the nature of alternating current, which gradually increases to maximum and their de-, creases to zero during each alternation. the force exerted on armature 32 is pulsating and pulsates with the frequency of the alternating current supplied to thecoil' 29. At each alternation of the alternating current, whose effective 'alue is above a certain predetermined amount determined by the tension of the spring 42, armature 32 vibrates in synchronism with the alternations of such current. Therefore, at each alternation the dog 48 engages the ratchetwheel and drives the same forward the distance of one tooth simultaneously therewith. The brake-lmnds 80 are applied to the brake-drums 56 and prevent the ratchet wheel over-shooting or moving more than the distance which the dog 18 travels after engaging a tooth of said ratchet wheel. These l rakes also hold the mtchet wheel against rotation while the armature'inoves upward and disengages the dog from said wheel so that there is no retrograte movement of said ratchet wheel by reason of the pressure of the dog against the teeth on ac count of the tension of spring 51. The intermittent rotation of the ratchet wheel 55 69. The stop de y in contact with the stop arm '69 by the coil spring 64: surrounding shaft 62.

When the armature 32 is in normal or elevated poapparent that when the causes rotation of the shaft 54 and, through the medium of the pinion 57 and gear wheel '70, rotates shaft 62. The rotary movement of-gear wheel causes the movable contactor 17 to be brought into engagement with the stationary contactor 16 atthe same time causing the stop device 77 to travel away from the stop arm 69. -T e dIflVIIIgHIOVGInGIIt of shaft 62, which isxthat caused by the-ninion 57, is resisted by thecoilspring (it around shaft 62. When the relay is inoperative, this spring returns the parts carried or actuated by shafts 5i and 62 to normal position, which is thatiin which the indicating finger 60 points to zero'on the raduated dial 59; in which the stop device 7 bears against the stop arm 69; and in which the movable contactor 17 is'at its greatest distance from the station- 'arycontactor 16. r

. t is to be noted that the collar 68' to which the stop arm 69 is secured is rotatably adjustable on the boss 67 of the standard or upright 61. The stop arm. therefore, -may be adiusted to cause the shaft 62 to have a'greater or lesser, n-iovement. so as to cause th'e movable actuator to travel through a longer or shorter path during the actuation of the vibrating armature motor.

The [circumferential position of/the stop arm 69uietermines the zero point bf the time limit of the relay and therefore the rangeof movement conta'ctor 17 has to travel throi'lflfh before touching contactor 16. It is of course circumferential po: sition of the stop arm 69 is changed it is desirable to change the position of the indicating finger 60 on shaft 54 so that it will. point to .zero on the graduated dial when thestopdevice 77 is in contact with the stop arm 69.

In the drawings 1 have shown meshing gearwheels to decrease the speed 'of shaft 62, andconsequently that of the gear wheel 70 carrying the movable contactor 17 and in this way provide the relay with a longer maximum time limit. It is'apparent that theprincipleof operation would not be departed from if the contact-or 17 was mounted directly upon the ratchetwhecl 55. but in such case the maximum ti-mc'limit attainable would. be considerably less than obtained by gearing down the motion of said ratchet wheel.

The stationary cont-actor 16 made in two parts hinged together with one movable relatively to the'other. since there is a rub-- hing motion produced between the same and the movable contactor l7. and by reason of hinging theupper part to the lower part, good electrical contact is'assured.

Assuming that the vnormal load current in the electric circuit, in Fig. 1, is ten amperes, and it is desired to switch off the circuit after a certain definite length of time upon the occurrence o f twenty amperes or more in the circuit, say two seconds after the current increasesto twenty amperes or more. Assuming also 'that the ratio of the series transformer 15 isten to five amperes (ten amperes primary and five amperes secondary), tenamperes will flow in the secondary when twenty amperes flow in the primary. Under such conditions the spring 42, which, holds the armature 32 elevated,

is adjusted so that the armature will be at- 7 tion or speed of said wheel willtheretore be,fifty teeth per second. This. motion is transmitted through gears to the movable contactor 17, and by properly positioning the stop arm 69 the movable contactor will engage the stationary contactor 16 in a pe-' riod of time corresponding to one-hundred strokes of the armature 32. vWhen these contactors come together, the'solenoids 19,

21,0f the switches 13 are energized from the battery 22 and the switches are thereby immediately opened and the electric circuit disconnected, whereupontheiflow of alternating current ceases and armature 32 remains in its normal orelevated position against stop 37. At the same time the timing and controlling mechanism returns to its normal position through the action of the spring 64 on shaft 62, which is that in which the stop device 77 engages the stop arm 69, in which the indicating finger 60 points to zero on the graduated dial, and in which the movable contactor 17 is farthest from the stationary contactor 16.

In case the excess current above twenty amperes does not continue to flow for onehundred alternations, but for any reason decreases back to less than ten amperes in less time than is required to move the movable contactor 17 into engagement with the stationary contactor l6, armature 32 ceases to vibrate and the mechaniism'returns to its zero position without opening the solenoid switches 13.

It is to be noted that the cross sectional area of armature 32 is relatively small compared to that of the magnet or core 28, which causes the armature to be thoroughly saturated with magnetic fl-uX at current valuesv above a certain minimum, below which the relay will not operate successfully. By rea- It will therefore make fifty son of the saturation of armature 32 at all working currents above a certain minimum, failure to operate by reason of extraordinarily heavy currents is obviated. For example, if armature 32 is not sufiicientlysaturated'atten amperes, then upon the occurrence of say thirty amperes in the coil the armature will beheld .down against the pole 35 and would not'vibrate sufliciently to cause operation of the relay, but by making this armature of relatively small cross sectional area, heavy currents in coil 29 do not produce this effect. This is an important advantage since the over-load current which can occur in an electric circuit may run up to very' high values.

' By adjusting the brake-bands 80 so that they continuously rest upon the brake Wheels or drums 56, or by removing the spri g 64, a time record can be obtained of ax y flow of alternating current by means of the stationary graduated dial, or any other scale and the indicating finger attached to the axle 54.

The dial or scale is, of course, to have one,

division or graduation for each tooth of the ratchet wheel 55, hence the displacement of the indicating finger from zero will show the number of alternations of currents which i has passed through the coils 29. It is of course to be understood that the dial 59 and indicating finger-60 may be removed from the shaft 54 when the device is used otherwise than for ascertaining the number of alternations of current which has passed throughothe coil 29, but the device is equally operative for all its purposes even though said dial and indicating finger are retained upon the shaft 5 1.

I have shown in the drawings a single relay element for single phase circuits, but

it will be clear to those skilled in the-art that the device may be used in connection with multiple phase circuits, a relay element being used for each phase of the circuit; for exau'1ple,three relays'would be necessary in a three phase circuit.

' It will further bev apparent that this invention. may be modified in various ways without departing from the spirit of the same or sacrificing any of the advantages thereof.

Having thus described my invention, what 1. The combination of an alternating current circuit, solenoid-operated swltches in saidcircuit normally closing the same, a

vibrating synchronous motor responding to a certain predetermined flow of alternating current through, said circuit, a normally open battery circuit including the solenoids of said switches, and means to'close said battery circuit actuated by said vibrating m0tor.,

2. The combination of an alternating our rent circuit, a switch normally closing said circuit, a vibrating electrically operated synchronous motor responding to a certain pre determined flow of alternating current through said circuit, a control circuit including a solenoid for actuating said switch, and a pair of cointactors relatively movable and adapted to be brought into contact with each other by said electrically-operated motor, said contactors serving to establish current through said control circuit and energize said solenoid to actuate the switch and open the alternating current circuit.

3. The combination of an alternating current circuit, a transformer in said-circuit, a vibrating-armature synchronous motor connected with the secondary coil of said trans former and adapted to be placed into action at. a certain predetermined flow of alternating current throughsaid transformer, and positively driven means actuated by said motor to break the circuit.

, 4. The combination of an alternating current circuit, of mechanism responding to a certain, predetermined flow of alternating current through said circuit and adapted to produce a certain definite motion in a cer lain definite number of alternations within said circuit during which an overload current of greater value than the predetermined quantity remains in'the circuit, and positively driven means for breaking the circuit by means of said mechanism after a predetermined number of current alternations.

5. A relay comprising an alternating current magnet, a pivotallysecured armature vrent ma gnet, a vibrating armature associated therewith, a shaft. mounted for rotatable movement, a. ratchet wheel secured to said shaft, a dog on said armature actuating said ratchet wheel, a brake drum on said shaft, a brake band adapted to engage said b'ake drum during the attracted. movement of said armature, and means to establish a controlling circuitactuated by said shaft.

7. A relay comprising an alternating current motor, a shaft rotatably mounted, a prime mover secured to said shaft and actuated by said motor, a pinion on said shaft, a brake drum on said shaft, a brake band normally 1 out of contact with said brake drum and adapted to act against the latter when said prime mover is actuated by said motor, a second shaft, a gear wheel on said second shaft meshing with said pinion,

I means to hold said second shaft in a certain position circuinferentially, an electrical contact-or movable with said gear Wheel,a fixed electrical contactor-against which said firstmentioned contac-tor is adapted to engage when. said second shaft is rotated through a certain range of movement, and means to return said second shaft to normal position when it ceases to rotate.

8. A relay comprising an electric motor, a rotatable shaft, means actuated by said m0- tor for rotating said shaft, a cimcumferential ly adjustable stop; a stop device rotatable with said shaft and adapted to normally bear against said stop, an electrical contactor caused to travel through an arc of a circle during the rotation ofsaid shaft, an elec trical contactor against which said firstmentioned' contactor is adapted to engage to establish a controlling circuit, and means to reverse the movement of said shaft so as to return said stop device to normal position in contact with said circumferentially adjustable stop.

9. A relay comprising an alternating current magnet, an armature adapted for movement toward and from said magnet with the alternations of said current, a controlling mechanism including a ratchet Wheel, a dog and retain said overhanging stop in contact with said armature.

In testimony whereof lafiix my signature.

LLOYD O: NICHOLSON.

(topic: of thil patent may be obtained for five cents each, by addreislng thecommissioner of Intent],

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